I don't like classes in games with defined characters specifically because it makes those characters more wishy-washy. For instance, if you could equip Cinnamon from Mega Man X: Command Mission with a Mega Buster or the Z-Saber, why even bother having X and Zero? A character's abilities and weapons should be intimately tied to that character's personality and roots. They should be central aspects of defining that character.
On the other hand, if the game is more open-ended and the player is able to tailor the design of the entire party, there isn't a problem with allowing a transition of jobs and abilities. Personally I find games with less solid characters much more difficult to get into because I'm pretty big on exploring characters.
However, I think a balance could be found by taking the Sonic Battle approach to things and providing a single character that could be trained along a player-driven development path while the others are more defined.
On the other hand, if the game is more open-ended and the player is able to tailor the design of the entire party, there isn't a problem with allowing a transition of jobs and abilities. Personally I find games with less solid characters much more difficult to get into because I'm pretty big on exploring characters.
However, I think a balance could be found by taking the Sonic Battle approach to things and providing a single character that could be trained along a player-driven development path while the others are more defined.